Roboboffins have come up with a way to disguise their soft-bodied, multi-limbed robostarfish, by using colour to camouflage its silicone body.

Last year, Harvard researchers came up with a squishy cephalopod robot that could do the limbo, wriggling through a 2cm gap. Now the same scientists have figured out how to hide the octorobot, using the same tech to allow it to make a bold colour display.

If the squidgy robot could adopt a bright red hue on demand, this could act as a visual marker to help search crews during a disaster, or even help doctors plan complete surgeries.

"When we began working on soft robots, we were inspired by soft organisms, including octopi and squid,” lead author Stephen Morin said in a canned statement. “One of the fascinating characteristics of these animals is their ability to control their appearance, and that inspired us to take this idea further and explore dynamic coloration.”

Real animals might use a bold colour display to scare off predators or pretend to be another (preferably poisonous) type of starfish – in those cases camouflaging would obviously allow them to hide from other beasties.

To get the same result with their squidbot, the boffins pumped liquids into its silicone body via micro channels under the surface, created using 3D printers. Coloured liquids are injected for the bright displays but the boffins can also thermally hide the robot with heated or cooled liquids or make it glow in the dark with fluorescents.

"There is an enormous amount of spectral control we can exert with this system,” Morin said. “We can design colour layers with multiple channels, which can be activated independently. We’ve only begun to scratch the surface, I think, of what’s possible.” ®